1. Field of the Invention
The present invention relates to a method for correctly determining optimum recording power through detecting whether a radio frequency (RF) top channel signal is correct.
2. Description of the Related Art
Generally, optical recording media are divided, according to capability of repetitive recording, into a read-only memory (ROM), a write-once-read memory (WORM) capable of only one time of recording, and a rewritable memory (RW) capable of repetitive recording.
The ROM optical recording medium comprises a compact disc (CD)-ROM and a digital versatile disc (DVD)-ROM. The WORM optical medium includes a CD-recordable (CD-R) and a DVD-R which are both one-time recordable medium. The RW medium which can rewrite data many times includes a CD-RW and a DVD-RW.
In order to obtain high-quality optical recording, an optimum power control (OPC) process is indispensable. The OPC process is for determining an optimum recording power according to the recording medium and the discs having respectively different optical characteristics. In general, the OPC process is performed in a power calibration area (PCA) allocated beforehand on the disc according to the Orange Book which is the Trusted Computer Security Evaluation Criteria.
According to the Orange Book, a disc includes five areas depending on purposes. In other words, a disc is divided into a PCA area, a programmable memory area (PMA), a lead-in area, a data area, and a lead-out area.
In the PCA area, prior to actual data recording, test data is recorded while changing strength of a laser beam so that the optimum recording power corresponding to the disc can be determined. Usually, information on an empty CD of major manufacturers is already included in a recorder. The PMA area temporarily stores information on data being recorded before closing the disc. The lead-in area records a table of contents (TOC) which is information on recorded items. The lead-out area informs of an end of the recording. An area to the left of the data area, including the PCA area, the PMA area and the lead-in area, is referred to as an inner circumferential area, whereas an area to the right of the data area, including the lead-out area, is referred to as an outer circumferential area.
The DVD/RW is capable of recording, deleting and rewriting of data. Even in the PCA area which performs the OPC, if the PCA area is filled up with data, the data should be erased for reuse of the PCA area. Here, the PCA area may not be completely cleared due to an unstable servo and inferiority of power setting, or the data before emptying the PCA area may remain in the recording medium, thereby causing an error in the optimum recording power detected by the OPC.
Especially, the DVD/RW would have changes of spaces around a pit due to an influence of the optical power recorded before DC-erase (direct current-erase), which accordingly causes an error in the optimum recording power.